7 August 2010

Home improvements part 1: New deck

It occurred to me that I haven’t written about the epic home improvement odyssey we’ve been on for the last few months.

The story really started in the fall of 2005, a few months after we bought the house.

When it rains in Austin, it really rains. You can hear what a typical storm sounds like by downloading a recording I made. (It’s binaural, so listen with headphones for full effect.)

In the aftermath of our first couple of storms since moving in, I noticed that water had pooled up on the lower front deck of the house. I didn’t think too much of it at the time, but when it was still there the next day, I realized that the builders hadn’t left any gaps for drainage between the planks of the deck.

Months passed, occasional downpours struck, and I started to notice the paint peeling. Closer inspection revealed that the exposed wood was soaking up the moisture. This was not good.

We were still paying off the cost of the refrigerator and various other expenses, so I looked around for a quick temporary fix. I found a company that made a waterproof industrial PVC covering, and called some guys who lived near Dallas who would install it. They did a pretty thorough job, carefully sealing the gaps at the bottom of the pillars with industrial strength caulk. I thought the immediate problem was solved.

It wasn’t.

The next problem I noticed was some discoloration at the base of the vertical supporting pillars at the front of the house. Prodding at it revealed soft, pulpy, rotting wood. I got a contractor to patch it up.

By this spring, things had gradually progressed to a point where further patching wouldn’t be sufficient. Fairly large patches had rotten away at the base of two of the pillars, revealing that the pillars were hollow untreated wood. They shouldn’t have been used as load-bearing pillars at all, they were just decorative for use indoors. An indentation of the PVC and caulk around the third pillar revealed that it was sinking into the deck.

It was time to call in a professional. A realtor friend had recommended someone to take care of some random yard work, and he knew a guy who specialized in decks. I interviewed him, talked to him about the job, took a look at some pictures of his past projects, and decided he was someone I could work with.

The first stage was exploration. What exactly was underneath the PVC, and how bad was the damage by now?

To cut a long story short, the builders had constructed the deck using untreated interior tongue-and-groove planking, laid on top of untreated plywood. The plywood in turn rested on the main joists of the deck, one of which was upside-down, which was why the water was pooling. (Deck joists usually have a slight camber.)

Around and beneath the deck was a concrete wall, which they hadn’t put any ventilation grilles in. The walled off sub-deck area was then separated from the rest of the house foundations by a solid wall of cement blocks, with two small holes in.

So even once the water stopped leaking directly through the deck, moisture would get in via small cracks at the edges of the deck and via the front steps, and would collect in the unventilated area. The plywood was partially rotted, the planking was rotting, the pillars were rotting, water was getting in via the rotting hollow pillars and causing more rot, and the middle pillar didn’t have anything under the deck to support it. Oh, and the steps weren’t to building code–too steep. Basically, everything including the railings needed to be torn off, right down to the main joists, and the whole thing rebuilt–including redoing the steps from scratch, adding ventilation grilles to the walls, and putting a support in for the center pillar.

That was just the downstairs front deck.

The upstairs was the same basic construction–untreated interior planks on untreated plywood, hollow decorative pillars just about supporting the weight of the roof. The builders had actually bothered with some plastic sheeting to stop water from dripping through to the deck below–but the plastic stopped about 10cm short of the edge of the deck. So again, it was all pretty much a write-off.

Fixing all this was clearly way beyond anything I could have attempted myself. On both levels, the roof had to be jacked up and temporary supporting beams put in while the rotten pillars were removed.

So several months and thousands of dollars later, we basically have a whole new front deck. Some of the handrails were salvaged and reused, but that’s about it. No corners were cut, because the last thing I want to do is ever have another problem with this.

The deck surface is now thick treated wood planks, held down with galvanized deck screws. There are gaps between the planks for drainage, and three vents allow any moisture beneath the deck to evaporate away. The pillars are 15cm solid pressure-treated pine. They’re separated from the decks by surprisingly expensive galvanized metal spacers, which prevent water from pooling up and soaking into them at the base.

Upstairs required some inventive thinking. Normally you’d put what amounts to a miniature metal roof inside the floor of the upper deck, draining out of the front. Unfortunately, there wasn’t enough vertical space for that.

I checked reviews of various wood sealants designed for decks. I quickly came to the conclusion that while some of them claimed to have an 8 year warranty, none of them would actually last that long. Consumer Reports concluded that all the transparent or translucent sealants were basically worthless unless you were prepared to re-seal every few years.

I did more online searching, and found a company called Ames Research. They sell various rubber compounds which can be used for waterproofing, and are applied in liquid form. Their Super Elasto-Barrier dries to a pretty much untearable sheet of gray rubber, around 2mm thick. It’s usually used for waterproofing flat roofs. I figured if it was up to that task, it would probably cope with any rain that blew onto the deck and dripped through the gaps between the planks. As an added bonus, it’s water-based, so we didn’t have to worry about lots of noxious volatile chemicals harming the parakeets.

So, the treated plywood was coated with rubber; then some spacer joists were fixed to it; then the whole lot was given several more coats of rubber. The result is a flat, ribbed, rubber-sealed surface that slopes gently towards gaps at the front of the house, and drains away any water that falls through the upper deck.

I had also checked Consumer Reports and a few other sites to find out what would be appropriate for paint. Valspar and Behr got good reviews from CR after the equivalent of 9 years of exposure. There seemed to be a lot of people online with assorted grievances about Home Depot and Behr, so we went with Valspar and bought it from Lowe’s.

I’m completely happy with the end result. It looks much nicer than PVC, restores the original look of the house, and the steps are more comfortable to climb now.

The story isn’t over yet, though. Stay tuned for part two.

© mathew 2017